CVE-2026-65903 | DOMPurify before 3.4.0 contains a logic error in the ADD_TAG… | CVSS 6.1 MEDIUM

Description

DOMPurify before 3.4.0 contains a logic error in the ADD_TAGS function where short-circuit evaluation allows forbidden tags to bypass FORBID_TAGS restrictions. Attackers can craft input containing tags listed in FORBID_TAGS that are also added via ADD_TAGS function, causing them to be retained in sanitized output.

Metadata

CVE ID: CVE-2026-65903
State: PUBLISHED
Assigner: VulnCheck
Reserved: 2026-07-23 11:03 UTC
Published: 2026-07-23 13:16 UTC
Last updated: 2026-07-23 13:16 UTC
Primary CWE: CWE-697
Incorrect Comparison
Vendor / Product: cure53 / DOMPurify
Sources: cve.org · NVD

Severity & Metrics

6.1 MEDIUM CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products (1)

Vendor	Product	Platform	Versions
cure53	DOMPurify	—	0 < 3.4.0, 3.4.0

Weakness (CWE)

CWE	Source	Description
CWE-697	cna	Incorrect Comparison

CVSS scores (2)

Score	Severity	Version	Source	Vector
6.1	MEDIUM	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.1	MEDIUM	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

References (2)

GitHub Security Advisory (GHSA-39q2-94rc-95cp) https://github.com/cure53/DOMPurify/security/advisories/GHSA-39q2-94rc-95cp
VulnCheck Advisory: DOMPurify before 3.4.0 ADD_TAGS Function Bypasses FORBID_TAGS https://www.vulncheck.com/advisories/dompurify-before-add-tags-function-bypasses-forbid-tags